This invention relates to a screw equipped with a locking means, more particularly to a screw equipped with a locking means which not only can prevent the screw from being loosened by, for example, vibration or shock, but also will enable a shortening of the assembly steps by obviating such work as the insertion of a packing or spring washer, or the injection of an adhesive for the prevention of looseness, simultaneously with realizing a saving of the parts to be used.
A conventional screw, as can be seen from the sectional view shown in FIG. 1 (A), has a means for preventing looseness which clamps a member to be fixed, for example, a plate 3, with a bolt 1 and a nut 2 with a packing or spring washer 4 interposed therebetween. Also, as a means of enabling a more complete fixing, an adhesive has been injected at the fitting portion 5 between the bolt 1 and the nut 2 (the sectional view shown in FIG. 1 (B) shows an example of an anchor bolt).
However, according to such a prior art method, a separate material such as a spring washer or adhesive is required and the step of mounting the spring washer 4 or injecting adhesive is required. Further, the adhesive force of the adhesive will be inevitably lowered by change over a period of time. When the screw is to be repeatedly detached, it is impossible to use an adhesive and further, the function of the spring washer 4 will be inevitably degraded, or abrasion will occur after repeated use. Such problems will occur more markedly when the material of the screw consists of different substances.